The present invention relates to a bag for containing items, such as consumables. More particularly, the invent ion is directed to a bag having a built-in closure tab.
Bags, such as film bags, are utilized extensively in modern society for containing a wide variety of items, such as candies, food items and liquids. A typical film bag is made from a laminate that includes an outer film layer adhesively secured to an inner sealing layer. The outer layer is usually made from a material that facilitates printing. The inner layer is usually made from a material that enables the package to be sealed. Other layers can also be incorporated. Properties, such as permeability to oxygen and moisture, strength, stiffness and other packaging requirements may dictate material selection. The outer and inner layers are both typically made from plastic film, such as polyethylene or polypropylene.
The conventional bag is closed by bringing two opposing sides into contact and downwardly folding or rolling them together. When closed, the bag may tend to free itself from the rolled configuration, thereby reopening and exposing its contents to ambient air. Various methods of preventing the conventional bag from reopening have been attempted. Household items such as clothes pins or paper clips have been used to hold the conventional bag closed. Articles of manufacture, such as the Chip-Clip(copyright) (a registered trademark of the Chip Clip Company of Dallas, Tex.), have been specially designed as closures for bags.
Other attempts to provide a closure mechanism for a conventional bag have tried to provide a closure device with the bag itself. Some bags have been provided with a metal wire or strip along the length of the bag, the wire or strip being easily bent under the user""s manipulation, but resisting the tendency of the bag to open once folded, thus keeping the bag closed. An example of such a bag is disclosed by U.S. Pat. No. 3,618,850 to Palmer. Other bags are provided with nonresiliently flexible strips disposed transversely to the length of the bag. The nonresilient strip is along the top of the bag and extends beyond the side of the bag. Once the top of the bag is rolled down a first side, the extending portion of the strip is folded snugly against a second side, opposite the first side, preventing the bag from unrolling.
Still other attempts to seal a bag involve retrofitting a tab or label onto the bag. A first portion of the label is attached to a bottom portion of the bag with a permanent adhesive. The label has a second portion on which a releasable adhesive is disposed. When the bag is closed and folded downwardly, the portion with releasable adhesive may be attached to the folded portion, thereby preventing the bag from unrolling. One example of a bag of this type is disclosed by U.S. Pat. No. 5,582,889 to Pedrini. One problem with a retrofitted closure tab is the expense of manufacturing and handling the tab.
It is desirable to provide a bag having a closure device which is not as complex or expensive to produce as those described above.
The invention is directed to a bag with a reusable built-in closure tab. The closure tab is formed from the outer layer of the laminate which forms the sides of the bag. Thus, the closure tab is xe2x80x9cbuilt-in.xe2x80x9d
A bag according to the present invention has an inner and an outer layer. A portion of the outer layer is defined as a tab. The tab portion is separated from the remainder of the outer layer (the fixed portion) by precision cutting. After cutting, the tab portion remains attached to the fixed portion only at its base. A pressure sensitive adhesive, rather than a permanent adhesive, is disposed on the under side of the tab portion, attaching the tab to the inner layer. Thus, the tab portion may be easily pulled away from the inner layer, although remaining attached at its base. The pressure sensitive adhesive disposed on the inside of the tab may be used to affix the tab to a rolled down portion of the bag, thereby sealing the bag closed.